Update statistics
Hi All,
Getting below error:
update statistics low using sampling may generate inaccurate index statisticsfor index 'some column' due to data skew
Thanks
This is a warning saying that the index sampling did not work because of
the extreme index skew. This just means that we fall back to the previous
method and statistics are generated. This is just a performance warning
for update statistics. I believe you might have an environment variable
set which turns on an update statistics low optimization.
John F. Miller III
STSM, Lead Architect
miller3@us.ibm.com
503-747-1366
IBM Informix Dynamic Server (IDS)
ids-bounces@iiug.org wrote on 09/14/2015 11:37:33 PM:
> From: "J KHANNA" <jaya.chhatlani@gmail.com>
> To: ids@iiug.org
> Date: 09/14/2015 11:38 PM
> Subject: Update statistics [35787]
> Sent by: ids-bounces@iiug.org
>
> Hi All,
>
> Getting below error:
>
> update statistics low using sampling may generate inaccurate indexstatistics
> for index 'some column' due to data skew
>
> Thanks
>
>
>
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> Forum Note: Use "Reply" to post a response in the discussion forum.
>
It's not an error but a warning. You can get rid of the warning by turning
LOW mode sampling off by setting the ONCONFIG variable USTLOW to zero (0).
Or you can disable it for this single table by setting the environment
variable USTLOW_SAMPLE to 0 either in the session's environment or using
the SQL statement "SET ENVIRONMENT USTLOW_SAMPLE=0;" before running update
statistics for this table.
Art
Art S. Kagel, President and Principal Consultant
ASK Database Management
www.askdbmgt.com
Blog: http://informix-myview.blogspot.com/
Disclaimer: Please keep in mind that my own opinions are my own opinions
and do not reflect on the IIUG, nor any other organization with which I am
associated either explicitly, implicitly, or by inference. Neither do
those opinions reflect those of other individuals affiliated with any
entity with which I am affiliated nor those of the entities themselves.
On Tue, Sep 15, 2015 at 2:37 AM, J KHANNA <jaya.chhatlani@gmail.com> wrote:
> Hi All,
>
> Getting below error:
>
> update statistics low using sampling may generate inaccurate index> statistics
> for index 'some column' due to data skew
>
> Thanks
>
>
>
>
*******************************************************************************
> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>
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